(pPOK = has string)

>perl -MDevel::Peek -MData::Dumper -e"$_=0.42; Dumper($_); Dump($_);"
SV = NV(0x3335fc) at 0x328fe4
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  NV = 0.42

>perl -MDevel::Peek -MData::Dumper -e"$_={ qux => 42 }; Dumper($_); Dump($_->{qux});"
SV = IV(0x57b260) at 0x57b264
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 42

>perl -MDevel::Peek -MData::Dumper -e"$_={ qux => 0.42 }; Dumper($_); Dump($_->{qux});"
SV = PVNV(0x5490e4) at 0x25b264
  REFCNT = 1
  FLAGS = (NOK,POK,pNOK,pPOK)
  IV = 0
  NV = 0.42
  PV = 0x4c9f84 "0.42"\0
  CUR = 4
  LEN = 36